Thanks for posting your question here. In order to remove the Auctiva scrolling gallery from listings which are already active, you would have to delete the HTML code used to generate the scrolling gallery from the description HTML of each listing using eBay's "Revise your Item" form.
You can view the full HTML code used to generate your scrolling gallery by mousing over the "Stores" tab within your account and selecting the "Get HTML" option under "Scrolling Gallery". It is most easily identified by the <!--ASW--> tags that mark the beginning and end of the code.
If you also wish to prevent the scrolling gallery from being added to any of your new listings, you can accomplish that by mousing over the "My Account" tab within your account, selecting the "Acct Preferences" option under "Settings", selecting "No" from the drop down menu next to "Append Auctiva Scrolling Gallery to my listings", and then clicking the "Update Account Preferences" button below.
If you need any further assistance with your account, please feel free to contact our customer support team by mousing over the "Help" tab and selecting the "File Support Case" option.